Inorganic CsPbI3 perovskite quantum dot (PQD) receives increasing attention for the application in the new generation solar cells, but the defects on the surface of PQDs significantly affect the photovoltaic performance and stability of solar cells. Herein, the amino acids are used as dual‐passivation ligands to passivate the surface defects of CsPbI3 PQDs using a facile single‐step ligand exchange strategy. The PQD surface properties are investigated in depth by combining experimental studies and theoretical calculation approaches. The PQD solid films with amino acids as dual‐passivation ligands on the PQD surface are thoroughly characterized using extensive techniques, which reveal that the glycine ligand can significantly improve defect passivation of PQDs and therefore diminish charge carrier recombination in the PQD solid. The power conversion efficiency (PCE) of the glycine‐based PQD solar cell (PQDSC) is improved by 16.9% compared with that of the traditional PQDSC fabricated with Pb(NO3)2 treating the PQD surface, owning to improved charge carrier extraction. Theoretical calculations are carried out to comprehensively understand the thermodynamic feasibility and favorable charge density distribution on the PQD surface with a dual‐passivation ligand.

The interfacial recombination at the perovskite/hole conductor interface generally results in significant energy losses in inverted perovskite solar cells (PSCs) with a p−i−n device architecture. Herein, a chemical bridge is built at the interface of poly(triarylamine) (PTAA)/perovskites by using 3-(1-pyridinio)-1-propanesulfonate (PPS) molecules to minimize interfacial recombination of charge carriers. Extensively theoretical calculations and experimental studies reveal that the pyridine of PPS molecule and the phenyl group of PTAA could be chemically coupled through π−π stacking, and the sulfonate at the other end of PPS molecule could anchor perovskites through a strong SO••• Pb coordination bond. The chemical bridge structure significantly suppresses charge carrier recombination at the interface of PTAA/ perovskites. Meanwhile, after incorporation of PPS molecules as an additive in the perovskites to effectively passivate surface defects of perovskites, an efficiency of up to 21.7% with negligible hysteresis is achieved for inverted PSCs.

Inorganic CsPbI3 perovskite quantum dot (PQD) shows a high potential for photovoltaic applications. However, the surface matrix of the PQDs significantly suffers from deterioration during the purification process with antisolvent,...

Broader contextUltra-flexible and lightweight solar cells with high power output per weight have attracted much attention due to their high potential for utilization in applications such as spacecraft, aircraft, personal pack load and wearable electronic devices. PbS colloidal quantum dots (CQD) are promising candidates for the fabrication of flexible and lightweight solar cells due to their nanocrystal character, which enables functioning energy conversion even in the case when the solar cell is under extreme deformation. Moreover, the PbS CQD possesses the advantages of solution-processability, size-dependent optoelectronic properties and a broad light absorption spectrum covering the ultraviolet-visible-near infrared wavelength region. In this study, we report an ultra-flexible and extremely lightweight PbS CQD solar cell. The solar cell is fabricated on a 1.3 mm-thick flexible polyethylene naphthalate foil substrate and an Ag nanowire network with strong mechanical properties and a large aspect ratio and is used as a transparent and conductive front-electrode. The thickness of the full solar cell is less than 2 mm and the device gives B10% power conversion efficiency with an extremely low weight of 6.5 g m À2 , resulting in a high power-per-weight output ofThe demonstrated CQD solar cell shows good mechanical properties and works during large compression-stretching deformation. In particular, the solar cell also exhibits promising stability both under continuous illumination and after storage under ambient conditions. These results reveal that the CQDs are very promising materials for realizing flexible, efficient and extremely lightweight solar cells that makes it possible for utilization of solar energy in many new applications.

Lead halide perovskite quantum dots (PQDs), also called perovskite nanocrystals, are considered as one of the most promising class of photovoltaic materials for solar cells due to their prominent optoelectronic...

Surface properties of colloidal quantum dots (CQDs) are critical for the transportation and recombination of the photoinduced charge carrier in CQD solar cells, therefore dominating the photovoltaic performance. Herein, PbS CQD passivated using liquid-state ligand exchange (LSLX) and solid-state ligand exchange (SSLX) strategies are in detail investigated using photoelectron spectroscopy (PES), and solar cell devices are prepared to understand the link between the CQD surface properties and the solar cell function. PES using different energies in the soft and hard Xray regime is applied to study the surface and bulk properties of the CQDs, and the results show more effective surface passivation of the CQDs prepared with the LSLX strategy and less formation of lead-oxide. The CQD solar cells prepared with LSLX strategy show higher performance, and the photoelectric measurements suggest that the recombination of photoinduced charges is reduced for the solar cell prepared with the LSLX approach. Meanwhile, the fabricated solar cells exhibit good stability. This work provides important insights into how to fine-tune the CQD surface properties by improving the CQD passivation, and how this is linked to further improvements of the device photovoltaic performance.

An additional perovskite stacking layer is in situ grown on the top of a perovskite layer forming a perovskite stacking structure to improve the interfacial properties at the perovskite/carbon electrode interface.

Summary Infrared PbS colloidal quantum dot (CQD)-based materials receive significant attention because of its unique properties. The PbS CQD ink that originates from ligand exchange of CQDs is highly potential for efficient and stable infrared CQD solar cells (CQDSCs) using low-temperature solution-phase processing. In this review, we present a comprehensive overview of CQD inks for the development of efficient infrared solar cells, which can effectively harvest the photons from the infrared wavelength region of the solar spectrum, including the importance of infrared absorbers for solar cells, the unique properties of CQDs, ligand-exchange determined CQD inks, and related photovoltaic performance of CQDSCs. Finally, we present a brief conclusion, and the possible challenges and opportunities of the CQD inks are discussed in-depth to further develop highly efficient and stable infrared solar cells.